• Journal of Powder Materials
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• v.20 no.1
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• pp.48-52
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• 2013

A study of oxidation kinetic of Fe-36Ni alloy has been investigated using thermogravimetric apparatus (TGA) in an attempt to define the basic mechanism over a range of temperature of 400 to $1000^{\circ}C$ and finally to fabricate its powder. The oxidation rate was increased with increasing temperature and oxidation behavior of the alloy followed a parabolic rate law at elevated temperature. Temperature dependence of the reaction rate was determined with Arrhenius-type equation and activation energy was calculated to be 106.49 kJ/mol. Based on the kinetic data and micro-structure examination, oxidation mechanism was revealed that iron ions and electrons might migrate outward along grain boundaries and oxygen anion diffused inward through a spinel structure, $(Ni,Fe)_3O_4$.

• Fire Science and Engineering
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• v.15 no.2
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• pp.1-5
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• 2001

We had investigated combustion properties of starch. Decomposition of starch scavenged by pre-cipitator of spinning factory with temperature were investigated using DSC and TGA. Combustion properties of starch according to amount were checked as temperature variation according to time using spontaneous ignition apparatus. Moreover, combustion properties with blowing or without blowing condition were checked in spontaneous ignition apparatus. As results of thermal analyses, increase in raising temperature causes initial smoldering temperature to move towards low temperature section. In addition, as amount of starch was increased, initial smoldering temperature was lowered. All of combustion forms were smoldering combustion. Initial smoldering temperature was low more slightly with blowing condition than without blowing condition in spontaneous ignition apparatus, which condition made heating value high.

• New & Renewable Energy
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• v.16 no.2
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• pp.47-53
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• 2020

The amount of food waste and its water content depends on both the season and region. In particular, the water content typically varies between 73.8 wt.% and 83.3 wt.%, depending on the proportion of vegetables. Current food waste drying technologies are capable of reducing the water content to less than 10 wt.%, while increasing the heating value. Ongoing studies aim to utilize dried food waste as fuel. Food waste can be used to produce solid refuse fuel (SRF) by mixing it with various solid fuels or other types of waste. The analysis of specimens is very important when considering the direct combustion of food waste or its co-firing with solid fuels. In this study, the weight reduction of specimens after burning them in a small combustor, and compared with the results of thermogravimetric analysis (TGA). The concentration of various chemicals was also measured to define the characteristics of waste generation. Performed proximate analysis, elemental analysis, TGA, combustion experiment, the heating value, and derivative thermogravimetry (DTG).

• Transactions of the Korean hydrogen and new energy society
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• v.13 no.4
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• pp.270-278
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• 2002

Mg and Mg alloys are attractive hydrogen storage materials because of their lightweight and high absorption capacity. Their range of applications could be further extended if their hydrogenation properties and degradation behavior could be improved, The main emphasis of this study was to find an economic manufacturing method for Mg-Ti-Ni-H systems, and to investigate their hydrogenation properties, In order to examine hydrogenation behavior, a Sieverts type automatic pressure-composition-isotherm(PCI) apparatus was used and the experiments were performed at 423, 473, 523, 573, 623 and 673K. The results of thermogravimetric analysis(TGA) reveal that the absorbed hydrogen contents are around 2.5 wt% for ($Mg_9Ti_1$)-10 wt% Ni. With increased Ni content, the absorbed hydrogen content decreases to 1.7 wt%, whereas the dehydriding starting temperatures are lowered by some 70-100K. The results of PCI on ($Mg_9Ti_1$)-20 wt% Ni show that its hydrogen capacity is around 5.3 wt% and its reversible capacity and plateau pressure are also excellent at 523K and 573K. In addition, the reaction enthalpy, $\Delta$HD.plateau, is $30.6{\pm}5.7kJ/molH_2$.

• Journal of the Korean Chemical Society
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• v.55 no.5
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• pp.819-823
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• 2011

The relationship between the microstructure, mechanical properties, and oxidation behavior of pitch-, polyacrylonitrile (PAN)-, and Rayon-based carbon fibers (CFs) has been studied in detail. Three types of carbon fiber were exposed to isothermal oxidation in air and the weight change was measured by thermogravimetric analyzer (TGA) apparatus. After activation energy was gained according to the conversion at reacting temperature, the value of specific surface area and the surface morphology was compared, and the reaction mechanism of oxidation affecting development of pores of carbon fibers was examined. This study will lead to a new insight into the relationship between the microstructure and mechanical properties of carbon fibers.

• Composites Research
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• v.33 no.1
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• pp.25-29
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• 2020

A liquid crystalline thermosetting-epoxy-based composite was fabricated using diglycidyl ether of 4,4'-biphenol, tin(IV) oxide as a filler, and sulfanilamide as a curing agent. To investigate the thermal behavior, Thermogravimetric Analysis and Laser Flash Apparatus were performed using 3.0-7.0 wt% Tin(IV) oxide. The result showed that the activation energy and thermal conductivity were proportional to the amount of added filler.

• Carbon letters
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• v.5 no.3
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• pp.113-117
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• 2004

The mesophase pitch was prepared by adding 1~10 wt% of the borane-pyridine complex (BPC) to decant oil. It was prepared in a reactor held at $450^{\circ}C$ for 2 h in $N_2$ atmosphere. The mesophase pitches were analyzed using thermogravimetric analyzer (TGA), melting point apparatus, X-ray diffraction (XRD) and polarized optical microscope. The coke yield, softening point, toluene insoluble, density and content of anisotropy in the mesophase pitches were increased with BPC contents. The XRD profiles did not show any effect of addition of BPC on the formation of mesophase pitch, while the crystallinity of mesophase pitches was increased when the materials were heat treated with boron compound.

• Fire Science and Engineering
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• v.13 no.2
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• pp.26-32
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• 1999

We had investigated combustion pro야$\pi$ies of rice bran dusts. Decomposition of rice bran d dusts with temperature were investigated using DSC and the weight loss according to t temperature using TGA in order to find the thermal hazard of rice bran dusts, and the p properties of dust explosion in variation of their dust with the same particle size. Using H Hartman's dust explosion apparatus which estimate dust explosion by electric ignition after m making dust disperse by compressed air, dust explosion experiments have been conducted by v varying concen$\sigma$ation and size of rice br뻐 dust. According to the results for thermodynamic stability of rice bran dust, there are little change of initiation temperature of heat generation 때d heating value for used particle size. But i initiation temperature of heat generation decreased with high heating rate whereas d decomposition heat increased with particle size. Also, the explosion pressure was increased as t the ignition energy increased and average maximum explosion pressure was 13.5 kgv'cnt for 5 BJ/60 mesh and 1.5 뼈Ie미 dust concentration.

• Fire Science and Engineering
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• v.13 no.1
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• pp.3-10
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• 1999

We had investigated combustion properties of natural textile dusts. Decomposition properles of natural textile dusts scavenged by precipitator of spinning factoη were investigated using D DSC(Differential Scanning Calorimeter) and TGA(Thermogravimetric Analysis) by temperature c changes. Combustion pro야rties of natural textile according to size distribution and amount were c checked as temperature variation according to time using spontan$\infty$us ignition apparatus. M Moreover, combustion properties with blowing or without blowing condition were checked in order to investigate combustion prope$\pi$ies in spontaneous ignition apparatus according to flow c condition of air. As results of thermal analyses, increase in r머sing tern야:rature causes initial smold벼ng t temperature to move towards low temperature section 뻐d i띠디떠 smoldering temperature was d de$\sigma$eased more remarkably in atmosphere than in inert gas and that condition allowed heating v value to increase considerably. In addition, as amount and size distribution of natural textile d dusts were increased, i띠ti머 smoldering temperature was lowered. All of combustion forms were s smoldering combustion. Initial smold밍ing temperature was low more slightly with blowing c condition than without blowing condition in sp$\alpha$ltaneoUS ignition apparatus, which condition m made heatim;!; value high.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.48-48
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• 1999

티타늄 알루미나이드 합금은 이들의 강도나 고온 특성 때문에 초음속 비행기의 구조물질이나 수소를 연료로 사용하는 비행기의 엔진물질로 각광받고 있다. 그러나 티타늄 알루미나이드 합금들은 이들이 갖는 규칙적인 미세구조로 인하여 실온에서 낮은 연성을 나타내는 단점이 있다. 실온에서 낮은 연성을 갖는 티타늄 알루미나이드 합금의 단점은 텅스텐, 물리브덴, 니오비움, 탄타륨, 바나디움 등의 베타 안정화 물질들을 첨가함으로서 어느정도 극복되고 있다. 따라서 티타늄 알루미나이드 합금이 초음속 비행기의 구조 물질이나 수소를 사용하는 엔진 물질로 사용되기 위해서는 이 물질들의 산화연구가 필수적이다. 지금까지 티타늄의 산화연구에서 알루미늄이나 니오비움의 역할에 대해서는 여러 연구자들이 연구를 한 바 있다. Chaze와 Coddet는 알루미늄이 티타늄에서 산소의 용해도를 감소시키고, Chen과 Rosa는 니오비움이 티타늄에서 산화물 형성율을 낮춘다는 것을 각각 알아냈다. 그러나 지금까지 티타늄 알루미나이드의 산화연구는 충분하지 못했다. 지금까지 티타늄 알루미나이드의 산화연구에서 밝혀진 산화운동학의 내용은 가열온도와 가열시간에 따라 크게 다른 두 개 혹은 그 이상의 산화물을 갖는다는 것이다. 본 연구의 목적은 여러 가지 티타늄 알루미나이드 합금의 산화특성을 밝히는 것이다. 이를 위하여 첫 번째 실험은 실온 공기 중에서 자연적으로 산화된 여러 가지 티타늄 알루미나이드 합금들($\alpha$2,$\beta$,${\gamma}$)을 초고진공($\leq$10-11Torr)속에 넣고, 시료의 온도를 실온에서 100$0^{\circ}C$까지 변화시키면서 AES(Auger Electron Spectroscopy)와 ISS(Ion Scattering Spectroscopy)를 사용하여 각각의 온도에서 여러 가지 시료들의 표면조성을 조사했다. 두 번째 실험은 티타늄 알루미나이드 시료를 고순도 공기(hydrocarbon$\leq$0.1^g , pp m) 중에서 각각 $600^{\circ}C$에서 100$0^{\circ}C$까지 가열하여 산화시켰다. 이 시료의 산화도는 각각의 가열온도에서 가열시간을 변하시키면서 TGA(Thermogravimetric Apparatus)로 측정했다. 실온 공기중에서 자연적으로 산화된 여러 가지 티타늄 알루미나이드 합금들을 초고진공속에 넣어 100$0^{\circ}C$까지 가열한 실험에서는 이들 시료에 포함된 알루미늄의 양에 따라서 표면 조성이 크게 다른 것을 알 수 있었다. 그리고 고순도 공기 중에서 100$0^{\circ}C$까지 가열하여 산화시킨 티타늄 알루미나이드 산화물의 산화기구는 명백한 3단계 포물선 산화의 특성을 나타냈다.